Each year, 15-20% of North American children are born to mothers who have a mood disturbance (such as depression and/or anxiety) during pregnancy, One-third of these women are treated with a medication called a serotonin/norepinephrine reuptake inhibitor (SRI) antidepressant. In Canada, this means that ~20,000 children per year are born to mothers treated with SRIs. In spite of almost twenty years of research there is still a pressing need to determine if these medications might affect the child's development. For over 15 years, we have studied developmental and behavioral outcomes in children of depressed, SRI-treated mothers. Now, two studies report a high risk for autism spectrum disorder (ASD) in children of mothers treated with an SRI during pregnancy. This raises critical questions about how such antidepressant exposure and maternal depression during pregnancy could be related to ASD. We will investigate this question by analyzing datasets from BC to see if ASD is more common in children whose mothers were prescribed an SRI during pregnancy, and if there is a link between ASD diagnosis and maternal mood disturbances. We will use a combination of individual data linked with population data to study outcomes of all children born in BC between 2000 and 2009 (400,000 mothers and infants, 20,000 SSRI exposures, 11,000 ASD diagnoses). We will follow these children until the end of 2013 to determine whether they were diagnosed with an ASD by age 4. This study will be the first to address this issue using individual diagnostic information combined with population-based health data to examine the link between prenatal SRI exposure and ASD in the child. Our findings will provide information on the relationship between prenatal antidepressant exposure and the incidence of ASD, which might help clinicians manage mood disturbances in pregnant woman.